ATtiny85 and heat

I'm thinking about making Christmas ornaments using Adafruit neopixel rings and raw ATtiny85's using usb power sources. I happened to go back to a previous ATtiny85 that was running a blink type program, and it was running extremely hot. I burned my finger touching it. I also noticed that the bread board it was also partially melted. However, I would worry about putting something that hot on a Christmas tree or that could burn my relatives.

Now, I don't remember when I downloaded the blink program, but it may have been before I learned about the burning bootloader step, so it may have been running at 1Mz with 5v with default flags.

What do I need to do to make sure the processor won't run as hot, even if it is going to be running for hours? Is doing the burning bootloader enough (short runs don't seem to run at hot). Or do I need some extra components/programming to get the chip to run without going to excessive temps?

I am a software guy, who is learning as he is going. Thanks in advance.

BTW, it is harder to type with a bandage over my burned index finger. :fearful:

these chips do not run that hot. it has nothing to do with bootloaders or any other software. even if one or two pins are shorted they will barely get warm. yours has most certainly suffered some kind of abuse such as overvoltage or cmos latchup. a new part is in order even if that one seems to function it cannot be trusted. more care to wiring next time.

Ok, thanks. I didn't recall my other ATtiny85's running that hot.

Given the cost of the ATtiny85's, I think I will throw it away, and the partially melted bread board also. Better safe than sorry.

My ATtiny 85 chips often get really hot too! But that's because at some point I accidentally flip them around and hook them up upside down!! That puts V+ on GND and vice versa.



oh yeah... i forgot about the ol plug-em-in backwards trick. depending on the supply they may or may not continue to work afterwards. i got a whole box of those. however even though they seem to work its not a good idea to trust them. you could chase your tail for hours because a slightly "bent" chip aint behaving exactly as expected.

i have another box full of avrs that i made a mistake with the fuse bytes. but thats a whole other story.